In a pneumatic tire, in order to sufficiently exhibit characteristics of its various portions, a tread rubber component, a sidewall rubber component, a clinch rubber component and an inner liner rubber component are made of different compounds. Further, when the pneumatic tire is to be produced, the rubber components mentioned above are extruded into different cross sectional shapes and are supplied to a tire former.
In recent years, a strip wind method is proposed to form the rubber components. According to the strip wind method, as shown in FIG. 7(A) for example, a ribbon-like unvulcanized rubber strip “a” is continuously wound around a tire former (not shown) spirally, thereby obtaining a rubber component b having desired cross sectional shape. FIG. 7(A) shows a tread rubber component c as one example of the rubber component b.
Further, in recent years, a dual wind method is proposed as shown in FIG. 7(B). According to this method, two rubber strips a1 and a2 are simultaneously wound around the former from opposite ends thereof in its widthwise direction toward its center. FIG. 7(C) shows another example of the dual wind method. According to this method, two rubber strips a1 and a2 are round around the former from its center toward its opposite ends.
In the dual wind method, it is necessary to simultaneously supply a plurality of rubber strips to the tire former. Therefore, the conventional method requires extruders for extruding compounded rubber in accordance with the number of rubber strips. The conventional method as a problem that the number of extruders is increased and equipment cost is increased.